Pituitary apoplexy secondary to immune‐mediated thrombocytopenia, with refractory severe hypernatremia in a dog

Abstract A 9‐year‐old, female, neutered Swedish Valhund was referred for progressive obtundation and development of petechiae. Neurological examination was consistent with a diffuse forebrain and brainstem neuroanatomical localisation. Severe thrombocytopenia was documented with investigations indicative of primary immune‐mediated thrombocytopenia. The dog was subsequently found to have persistent severe hypernatremia 5 days after initial presentation, which was refractory to intravenous fluid therapy. Euthanasia was requested due to the lack of clinical improvement. Postmortem brain magnetic resonance imaging identified an ovoid suprasellar area of suspected haemorrhage, most likely consistent with pituitary apoplexy. This is the first report describing pituitary apoplexy with refractory severe hypernatremia secondary to immune‐mediated thrombocytopenia in a dog.